Process for preparing fire retardant composition

ABSTRACT

A process is disclosed for adjusting the viscosity of trisdichloropropyl phosphate by admixing it with between about 5 and 30 percent, by weight, of a chlorinated naphthalene. The resulting formulation may then be conveniently employed as a fire-proofing composition, particularly for spinning baths for synthetic fibers.

United States Patent COMPOSITION 3 Claims, No Drawings U.S. C1 106/15, 106/165,106/177, 106/190, 252/8.1 Int. Cl. C09d 5/18, C091: 3/28 [50] Field of Search 106/15, 16, 165, 177, 190; 117/136; 260/457 P; 252/8.1

[56] References Cited UNITED STATES PATENTS 3,067,149 12/1962 Dombrow et a1. 260/25 3,202,567 8/1965 Muri et a]. 106/15 UX 3,403,118 9/1968 Listner 260/457 X FOREIGN PATENTS 874,762 8/1961 Great Britain 106/15 Primary Examiner Lorenzo B. Hayes Attorneys-Wayne C. J aeschke and Martin Goldwasser ABSTRACT: A process is disclosed for adjusting the viscosity of tris-dichloropropyl phosphate by admixing it with between about 5 and 30 percent, by weight, of a chlorinated naphthalene. The resulting formulation may then be conveniently employed as a fire-proofing composition, particularly for spinning baths for synthetic fibers.

- PROCESS FOR PREPARING FIRE RETARDANT COMPOSITION RELATED APPLICATION This is a continuation-in-part of application Ser. No. 679,542, filed Oct. 31, 1967, now abandoned.

BACKGROUND OF THE INVENTION In the process of producing synthetic fibers, it is the practice to press a viscous mass out of a fine aperture and by means of a subsequent stretch treatment, the coagulated filament is wound in some suitable manner. The pressing of this viscous mass, through apertures, into the form of a continuous filament is commonly known as spinning. Thus, in order to produce a suitable filament, a spinning solution must first be prepared. The solution must be suitably tenacious and viscous so that it can be pulled into fine filaments of great length. It must also have the property of hardening quickly in this form and it must produce a filament of proper strength and elasticity which can be readily handled and used. The solution should further have the desirable characteristic of having a stable and controllable viscosity under specified conditions. It should also have a certain toughness which permits not only generation of the thread, but its further stretching, without breaking, before reaching its fixation point.

The viscosity of the spinning solution is dependent on the molecular structure and attraction of the fluid and this, in turn, is influenced by the concentration and the size of the molecules of the ingredients contained therein. There are also limits to its viscous properties which must not be exceeded. Thus, if the viscosity is inordinately increased, it would be difficult to force the mass through the fine apertures, even under very high pressure. And, even if spinning could be accomplished under such conditions, the speed of thread formation would be too slow for commercial production. As a general principle, it may be stated that those spinning solutions that are most desirable have a sufficiently high viscosity to give form and strength to the resulting filament while at the same time possessing sufficient fluidity for rapid filament formation.

With the advent of more strict specifications for synthetic fibers, various additives have been proposed for incorporation into'spinning solutions in order to provide specific properties to the end product. One such class of additives is intended to provide the fiber filament with fire retardant properties. However, any additive that may be added to the spinning solution must have a viscosity within fixed limits so as not to disturb the overall viscosity of the spinning solution. One such fire retardant additive is tris-bromochloropropyl phosphate. This material provides the requisite fire retardant properties and has the proper viscosity limits to permit its being incorporated within spinning solutions used for the formulation of rayon or other synthetic fibers. The tris-bromochloropropyl phosphate can be formulated by either (I) reacting phosphorus oxytribromide with epichlorohydrin or (2) by reacting phosphorus oxytrichloride with epibromohydrin. However, in either case it is difficult to obtain the desired derivative in a high degree of purity. Thus, all the materials resulting from either of the above described reactions are impure and require extensive distillation and/or stripping prior to their being incorporated within a spinning solution. Thus, the problems of cost, purification and undesirable properties severely increase the cost of the desired end product.

In order to obviate these problems, it has been proposed to employ the less costly tris-dichloropropyl phosphate as a fireproofing agent for spinning baths. It can be manufactured by reacting phosphorus oxychloride with epichlorohydrin. However, this material ordinarily has too low a viscosity and cannot, therefore, be used in spinning baths. Various additives have been proposed for incorporation into the trisdichloropropyl phosphate in order to adjust its viscosity but such additives have impaired its fire retardant properties.

Thus, there has been a long felt need in the synthetic fiber industry for a low cost fire retardant material such as trisdichloropropyl phosphate, having the requisite viscosity properties for incorporation within synthetic fiber spinning solutrons.

TECHNICAL DISCLOSURE OF THE INVENTION It has been discovered that tris-dichloropropyl phosphate can be provided with a viscosity that renders it usable within spinning solutions by intimately admixing, therewith, a material which adjusts its viscosity without impairing its fireproofing characteristics. Thus, His-dichloropropyl phosphate is provided with the requisite viscosity by incorporating, therein, from about 5 to about 30 percent, by weight, ofa chlorinated hydrocarbon which is, preferably, a chlorinated aromatic such as naphthalene. The viscosity of the resulting blend is substantially increased, thus making it usable within synthetic fiber spinning formulations.

In the practice of the present invention, tris-dischloropropyl phosphate is first prepared by means of a suitable procedure such as by reacting phosphorus oxychloride with epichlorohydrin. The conditions under which the reaction takes place are well known in the art. As thus prepared, the tris-dichloropropyl phosphate has a viscosity of about 1,200 centipoise which makes it inappropriate for use with synthetic fiber spinning solutions. Thus, the viscosity of this material is adjusted by incorporating, therein, from about 5 to 30 percent, by weight, of a chlorinated naphthalene such, for exam ple, as the product sold under the trademark HALOWAX 0077 by Koppers Co., Inc., Pittsburgh, Pa., which has a chlorine content of about 60 percent, by weight, the use of the latter product being preferred in the process of this invention.

These chlorinated naphthalenes may be defined as fire resisting saturants having a high degree of thermal stability. Thus, they are refined chlorinated terphenyls having a chlorine content of from about 20-70 percent, by weight. They are noncorrosive to metals and are not hydrolyzed by water, alkali or acids. And, owing to their high chlorine content and low volatility, they are fully compatible with trisdichloropropyl phosphate although they have not, heretofore, been disclosed as viscosity improver therefor.

The chlorinated naphthalenes are incorporated into the dichloropropyl phosphate either at room temperature or, preferably, at elevated temperatures of about C. until a homogeneous mixture is obtained having a viscosity of between 1,400 and 12,000 cps. at 23 C. The resulting fire retardant blend can then be incorporated into synthetic fiber spinning solutions in a conventional mannerv The amount of fireproofing material that is added to the spinning solution will depend on the fireproofing characteristics desired in the final fiber product. Thus, up to about 30 percent, by weight, can be added to a spinning solution.

The following examples illustrate the merits of the present invention.

EXAMPLE I Tris-dichloropropyl phosphate was first formed by reacting phosphorus oxychloride with epichlorohydrin. To the resulting reacting phosphorus oxychloride with epichlorohydrin. To the resulting reagent there was then added varying amounts of a chlorinated naphthalene in order to adjust the viscosity thereof. The particular chlorinated naphthalene used in this experiment was purchased from the Koppers Co., Inc. and sold under the trade name ofI-IALOWAX 0077." In each instance, the chlorinated naphthalene was mixed with the trisdichloropropyl phosphate at a temperature of 100 C., until a homogeneous mass was obtained. The viscosity was then measured on a Brookfield Viscometer operating with a number 4 spindle at 60 r.p,ms at 23 C. The results of these tests are as follows:

TABLE 1 Percent tris- Percent dichloropropyl Chlorinated Viscosity Phosphate Naphthalene cps Stock 100.0 1,280 A 86.3 13.1 2.940 B 8111 18.9 6550 C 800 20.0 7.000 D 70.0 30.0 10,000 E EXAMPLE ll Each of the stocks of Example I were incorporated into a conventional rayon spinning solution in an amount of percent, by weight, and tested for fire retardant properties using ASTM procedures D-1433-58. In this manner, it was found that Stock A burned readily while stocks B, C, D and E were self-extinguishing.

Variations may be made in proportions, procedures and materials without departing from the scope of this invention as defined in the following claims.

What is claimed is:

l. A process for adjusting the viscosity of trisdichloropropyl phosphate which comprises homogeneously admixing said tris-dichloropropyl phosphate with from about 5 to 30 percent, by weight, of a chlorinated naphthalene containing from about 2070 percent, by weight, of chlorine so that the viscosity of the resulting mixture is in the range of from between about 1,400 and 12,000 centipoise.

2. The process of claim 1, where said chlorinated naphthalene contains about 60 percent, by weight, of chlorine.

3. The process of claim 1, wherein the homogeneous admix ture of said tris-dichloropropyl phosphate with said chlorinated naphthalene is conducted at elevated temperatures of up to about C. 

2. The process of claim 1, wherein said chlorinated naphthalene contains about 60 percent, by weight, of chlorine.
 3. The process of claim 1, wherein the homogeneous admixture of said tris-dichloropropyl phosphate with said chlorinated naphthalene is conducted at elevated temperatures of up to about 100* C. 